Having never created a PM/Brawl mod before (though I've helped with one's design), I have a dream of creating a stage, so I'm going to see if it's feasible for me to do so. This thread is where I'll be chronicling my efforts. (Veteran modders: if tl;dr, I would appreciate any answers for my questions at the bottom of this post.)

Smashville is nice, but it's old, and the music isn't very hype. I want to make Scuttle Town from Shantae and the Pirate's Curse as a replacement stage. Here's my vision for this:

The subject matter would be very similar to Smashville: a neutral stage with a town in the background and several character cameos behind the fighters

Scuttle Town goes through several changes over the course of the game, which can be used as replacements for Smashville's visual time changes:

The randomized villagers / elements can be replaced with characters from game.

Pirate's Curse has plenty of awesome music that can be used on this stage for both the daytime and cursed versions.

There can also be a non-competitive ASL version where the fight takes place in the actual town. Specifically, this area would make for a unique stage.

The balloon can be replaced with Wrench.

A performing K.K. Slider could be replaced with a dancing Shantae, maybe.

There are some roadblocks and design choices to consider:

Should the actual stage remain a 3D model? Although this would clash aesthetically, it makes more sense for fitting character cameos on the stage behind the fighters, and is less disruptive for competitive play. It's probably preferable.

Should the characters be flattened like in Flat Zone 2? Probably only for the alternate version.

Custom assets should be created for the stage model. I might be able to make something passable on my own by modifying the existing stage model and using modified textures from Pirate's Curse. I need to take care in my redesign to ensure that visual references that might be used by competitive players are properly recreated (specifically, the white lights).

Proper sprite rips are necessary to recreate Scuttle Town as it appears in-game. Ripping textures from a memory dump is very difficult, as the game turns them into jigsaws when it loads them into memory (presumably to save memory). Besides the ludicrous number of man-hours that would be necessary to piece them back together, I can't fully reassemble background elements using this method; parts of them are obscured, so I have no reference for how they should be assembled. Hopefully I can contact some of the folks who worked on ripping Ducktales Remastered to help with this WayForward game too?

Different music between the daytime and cursed versions would be preferable. While Smashville already has the necessary music slots and time-based music mechanic, I'm not sure if the timespan can be altered.

I have no idea how flexible the randomized villager mechanic is. It may be necessary to settle for a fixed cast of cameo characters.

Ideally, the NPCs in Scuttle Town would wander about randomly, but true randomness might not be accessible for animations. I know that Fountain of Dreams in PM doesn't have randomized animations for the platforms.

Ideally, PM 3.6 and vBrawl versions should exist (though I will prioritize PM). I'm assuming that I can't create PAC files that would be compatible with both, as PM provides its own files for Smashville. Hopefully it's not difficult to revert PM's changes to make a vBrawl version, as I'm assuming the changes made are small. (I'm not sure what the changes might be. It doesn't modify the REL. I think they tweaked the platform animation? There might also be small size / blastzone changes. If I recall correctly, the fix for Ness' recovery here was made on PK Thunder itself, not by modifying the stage.)

Smashville seems like a pretty complex stage in terms of construction. It might be a good idea to start out small by creating the alternate version over a template or FD or something.

I'm torn as to whether the alternate verison's edges should be walkoffs, cliffs, or water. Maybe I'll just do all three and let people choose.

Soon, I'm going to dive into some tutorials and try to learn enough to create this stage on my own, but any assistance from veteran modders would be welcome and appreciated. In particular, I have these questions that I don't expect to be answered by general-purpose tutorials:

Do 2D sprite stage elements still have to be constructed with 3DS Max?

Can uncompressed textures be used in stages?

How do the randomized villagers work? Could they be replaced with 2D sprites at different coordinates?

Is it possible to make the K.K. Slider tracks (N07–N12) always play on STGVILLAGE_03/04?

How does the "flattening" effect in stages like Flat Zone 2 and Hanenbow work? Can it be applied to other stages?

Oh, I should probably post an update here. Since creating this thread, Smash Wii U modding has picked up, so I've been working on creating this into a mod for that game. When it's done, you'll be able to find it on my Gamebanana profile.